1. Field of the Invention
The present invention relates in general to a technique of determining image correction. More particularly, the invention relates to a method of determining image correction including the steps of obtaining image data representing a photographic frame image as source image data, effecting an image correction by a predetermined correction degree on the obtained source image data, thus generating corrected image data, displaying a correction reproduced image based on the corrected image data on a monitor, and fixedly determining a final correction degree for an image correction to be eventually effected on the source image data while monitoring the correction reproduced image.
2. Description of the Related Art
In recent years, the so-called “mini-lab” system (photographic printing system) has been in use widely. According to this system, based on source image data such as image data obtained by digitization of a photographic frame image formed in a photographic film by using a film scanner or image data obtained by direct digitization of a photographic image by a digital photographic apparatus such as a digital camera, an optical beam emitted from an exposure head is controlled to scan and expose a photosensitive material (e.g. print paper) with this controlled beam, thereby to form an image thereon and the resultant material (paper) printed with this image is outputted from the system. Such photographic printing system as above allows various image corrections on the source image data inputted thereto before making a photo print thereof, so as to make a photo print of improved quality. The available corrections include density correction for compensating for overexposure or underexposure, correction of partial dropouts or loss of gradation in the image resulting from backlight or flash photography, and a sharpening correction for improving loose focus. Further, with improvement in image processing technique in the photographic printing, the system makes also available such correction of image deterioration resulting from transverse chromatic aberration and distortion due to aberration characteristics inherent in the photographic lens used, image deterioration due to insufficient brightness in image field edge (insufficient peripheral light amount), unnaturalness of image due to excessive lens swing/tilt distortion.
However, while such various image corrections are made possible, the system generally requires an operator's visual judgment using a reproduced image displayed on a monitor in decision of correction(s) to be actually made by the system. Therefore, the operability of the system is essential if speedy and accurate judgment by the operator is to be expected.
On the other hand, a type of image processing apparatus is known, from e.g. Japanese Patent Application “Kokai” No. 2000-324339 (see paragraphs [0018] and [0042] and FIG. 5). This image processing apparatus includes a monitor for displaying a reproduced image based on image data obtained from an optically photographed image by using a photographic lens in order to allow appropriate corrections for image deterioration such as distortion, transverse chromatic aberration due to lens characteristics, insufficient peripheral light amount, out-of-focus etc., a correction specifying section for allowing an operator to decide whether to effect a correction on the image quality deterioration based on the reproduced image being displayed, a temporary correcting means for specifying an appropriate correction intensity for the image quality deterioration according to the operator's specification and then displaying a correction reproduced image on the monitor for each correction made, a correction intensity determining means for fixedly determining a final correction intensity based on the correction reproduced image displayed on the monitor by the correction specifying means, and a correcting means for effecting a final correction based on the determined final correction to obtain output image data.
A lens-related correction assisting screen of this known image processing apparatus is configured to display an image prior to the temporary correction as an image to be tested and an image after the temporary correction on which the operator judges whether to fixedly determine the correction intensity, with the former image being displayed on the right side of the screen and the latter image being displayed on the left side of the same. The image prior to the temporary correction is a reproduced (and uncorrected) image of an image recorded in a photographic film for which the operator has judged an image correction is needed or an image after a preset correction using a predetermined correction intensity. The lens-related correction assisting screen includes, at a lower portion thereof, a sharpness correction box, a peripheral light amount correction box, a vertical distortion correction box, a horizontal distortion correction box, a correction level box for determining the correction intensity and a temporary correcting button. In response to a single mouse click of the temporary correcting button, the correction (intensity) level is incremented/decremented. With this, coefficients used in a correction mathematical expression, e.g. coefficients in respective terms in the case of a higher-order, polynomial expression, are varied, so that a correction intensity is determined by the expression having the varied coefficients. Then, based on the correction intensity thus determined, a temporary correction is effected and the monitor displays the image after the temporary correction.
In the above-described image correction operation of the image processing apparatus, the monitor displays only the image used as a reference image and the image after the temporary correction. The apparatus does not allow operator's simultaneous visual comparison between an image corrected by a high correction intensity and an image corrected by a low correction intensity relative to the reference image by viewing of these images at one time on the screen. For this reason, after the operator finds that the temporary corrected image is approximate to an appropriate image, the operator still needs to effect, in a trial-and-error manner, a plurality of times of temporary corrections with slightly different correction intensities to eventually arrive at the appropriate image. This poor operability results in increase in the time required for the image correcting process.